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ThomasHabets / arping

ARP Ping
http://www.habets.pp.se/synscan/programs.php
GNU General Public License v2.0
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No buffer space available #53

Closed 8Loading8 closed 9 months ago

8Loading8 commented 9 months ago

Good afternoon.

I use the arping utility to check the availability of network nodes that do not respond to ping. In the evenings I ran into the problem that arping does not work

arping: lib net_write(): libnet_write_link(): only -1 bytes written (No buffer space available)

During the day the macs in arp are about 4372 and in the evening when arping is not working about 4463 During the day, the traffic is about 4 Gbit/s and in the evening about 8 Gbit/s

net.ipv4.neigh.default.gc_thresh1 = 1280
net.ipv4.neigh.default.gc_thresh2 = 5120
net.ipv4.neigh.default.gc_thresh3 = 10240

I tried to increase gc_thresh by 2 times but it didn't help

Perhaps you need to make some kind of tuning of the linux kernel so that arping works in the evenings?

ThomasHabets commented 9 months ago

I don't think those parameters should help. They are all about the kernel's ARP table, I believe, but arping sends raw packets without looking consulting the ARP table.

More likely using ifconfig or ip to change the txqueuelength or something should be more effective, like ip link set eth0 txqueuelen 2000.

This could also help the rest of your performance. I wouldn't be super surprised if running 8Gbps on (presumably) a 10Gbps interface would start running a bit full on txqueues.

You may want to look into enabling multiqueue for the NIC, and QoS, if you're running that hot.

8Loading8 commented 9 months ago

It helped. Thanks.